Monday, December 14, 2009

A Recent headlines claiming that exercise doesn't help you lose weight because it over-stimulates the appetite caused quite a stir in both the public and health community. After all, we've heard for years that exercise is an important facet in weight loss and health.

The controversy over a recent study.

The study that (in part) inspired the exercise controversy was published in the interactive research journal, PLOS One, in February 2009. Researchers analyzed weight loss in a controlled trial of 411 sedentary, overweight or obese postmenopausal women. This study was unique, because it was the first to look at actual weight loss versus what was predicted based on energy expenditure across different levels of exercise.

The women participated for six months in either a non-exercise group or one of three different exercise groups based on energy expenditure: four calories per kilogram (kg, equal to 2.2 lbs) per week, eight calories per kg per week (matching current exercise recommendations by leading health organizations) or 12 calories per kg per week. The average weight loss was 1.4 kg in the four calorie group, 2.1 kilograms in the eight calorie group and 1.5 kilograms in the 12 calorie group. All exercise groups had a significant reduction in waist size. While the first two exercise groups (four and eight kg) experienced actual weight loss closely matching predicted weight loss, the third exercise group (12 kg) had actual weight loss that was less than predicted. The researchers discussed that with higher energy expenditure, people might be compensating with higher calorie intake.

Debunking exercise-weight loss myths.

The media translated these findings into the message that exercise doesn't do you much good other than to make you eat more, and it got a lot of health experts riled up. Among them was Timothy Church, M.D., Ph.D., lead researcher on the PLOS One study and American College of Sports Medicine (ACSM) member. Church announced on the ACSM website that the news coverage misrepresented the facts, with a few key concepts left out of the dialogue:

* Weight maintenance is different from weight loss. People who lose weight and keep it off exercise to maintain weight.

* Considerations for children are different. The focus with children should be on physical activity and prevention of excess weight gain rather than weight loss.

* Weight management is most successful when it includes both physical activity and proper nutrition.

ACSM experts stress that there is strong evidence from the majority of the scientific literature that physical activity is an important component for initial weight loss.